Binding

Objects of class Binding encapsulate the execution context at
some particular place in the code and retain this context for future use.
The variables, methods, value of self, and possibly an
iterator block that can be accessed in this context are all retained. Binding objects can be created using
Kernel#binding, and are made available to the callback of
Kernel#set_trace_func.

These binding objects can be passed as the second argument of the
Kernel#eval method, establishing an environment for the
evaluation.